The problem is not new. The power to initially actuate a solenoid coil is much higher than that necessary to maintain the solenoid in the latched position. The magnetic circuit is different in these two conditions.
Some devices employ a power circuit having a pulsed square wave or rectified sine wave output. These devices lower the net RMS voltage and power to approximately 20% but they experience significant DC ripple which can cause the plunger within the solenoid to drop out. They also suffer from potential reliability problems because they are polarity sensitive. The input voltage tolerance to these devices is +/-10% and the DC ripple can be as much as 20% peak to peak. The input voltage tolerance is narrow because these devices do not have any output voltage sensing apparatus.